The nanomaterials, in particular- nano-particulate materials and nano-particulate oxides are used in wide range of applications: including but not limited to sensors, batteries, capacitors, photovoltaic cell (e.g. Dye Solar Cells), electrochromic devices, fuel cells and devices for photocatalytic cleavage and purification of water.
High commercial potential of Dye Solar Cell technology is achieved through the nano-particulate structure of oxide layer incorporating designed porosity, that warrants high surface area, and, thus,—enhanced ability to adsorb sufficient quantity of dye to effectively capture solar light on the interface between the dye layer and electrolyte.
It has been recognized that surface properties of nano-particles are critical for achieving high performance of devices based on nano-particulate materials.
Modifications of the said properties can be performed by covering each particle by a thin layer of another material. The purpose of such coating varies:
Creating a barrier layer (e.g. junction between two materials with different electronic properties). Benefits of the barrier layer include creation of internal electrical field, that allows for unidirectional transfer of electrons (diode effect).
Creating a blocking layer (electrical insulation of all or part of the surface of a particle from electrolyte or corrosive material).
Deposition of materials that absorb in the UV-Visual light—IR spectrum.
Electronic shielding of nano-structured oxides (NSO). Certain materials that reside adjacent to or in the surface of the NSO provide electronic shielding and, thus, prevent undesirable charge transfer through the interface between the surface and an electrolyte. This charge transfer causes leakage current: loss of voltage and undesirable side reactions, which lead to degradation of a device. Preferably the said Electronic Shielding Materials (ESM) are optically transparent and chemically stable.
Current methods include sol-gel chemistry and several different vacuum deposition techniques. Each technique is limited as each does not allow for fast and precise deposition and achievement of desirable properties of the layers.